RE: [PATCH v3 2/8] DT: reset: renesas,rzn1-reboot: document RZ/N1 reboot driver

[Michel Pollet]

Hi Rob,

On 09 April 2018 21:10,  Rob Herring wrote:
> On Thu, Mar 29, 2018 at 08:46:58AM +0100, Michel Pollet wrote:
> > The Renesas RZ/N1 Family (Part #R9A06G0xx) requires a driver as part
> > of the sysctrl MFD to handle rebooting the CA7 cores.
> > This documents the driver bindings.
> >
> > Signed-off-by: Michel Pollet 
> > ---
> >  .../bindings/power/renesas,rzn1-reboot.txt   | 20
> 
> >  1 file changed, 20 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt
> >
> > diff --git
> > a/Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt
> > b/Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt
> > new file mode 100644
> > index 000..f592769
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/power/renesas,rzn1-
> reboot.txt
> > @@ -0,0 +1,20 @@
> > +DT bindings for the Renesas RZ/N1 Reboot Driver
> > +
> > +== Reboot Driver Node ==
> > +
> > +The reboot driver is always a subnode of the system controller node,
> > +see renesas,rzn1-sysctrl.txt for details.
> > +
> > +Bindings:
> > ++ Required:
> > +compatible = "renesas,rzn1-reboot";
> > +
> > +Example:
> > +sysctrl: sysctrl@4000c000 {
> > +compatible = "renesas,rzn1-sysctrl", "syscon", "simple-mfd";
>
> Are there other functions for this block? If so, please define a complete
> binding for the block.

There are indeed multiple functions for this particular IP block. It's pretty 
much a
kitchen sink of clocks, pinmux, reboot, watchdog, SMP and probably a couple
more I forgot about!

We've discussed this MFD structure with Geert, we picked that because if I
were to add all these callbacks/drivers to a 'sysctrl' driver, it'd end up 
looking
like ... a mach-xx.c file in the end!
So the current version is just a placeholder for a single driver for now, but it
won't last, there's already a SMP core enable driver lined up next...

>
> > +reg = <0x4000c000 0x1000>;
> > +
> > +reboot {
> > +compatible = "renesas,rzn1-reboot";
>
> Why is this node needed? The driver for "renesas,rzn1-sysctrl" should be
> able to register as a reboot handler/driver/provider.

Please see above...

>
> Rob

Thanks for your input!
Michel




Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road, Bourne End, 
Buckinghamshire, SL8 5FH, UK. Registered in England & Wales under Registered 
No. 04586709.

Re: [PATCH v3 2/8] DT: reset: renesas,rzn1-reboot: document RZ/N1 reboot driver

[Rob Herring]

On Thu, Mar 29, 2018 at 08:46:58AM +0100, Michel Pollet wrote:
> The Renesas RZ/N1 Family (Part #R9A06G0xx) requires a driver
> as part of the sysctrl MFD to handle rebooting the CA7 cores.
> This documents the driver bindings.
> 
> Signed-off-by: Michel Pollet 
> ---
>  .../bindings/power/renesas,rzn1-reboot.txt   | 20 
> 
>  1 file changed, 20 insertions(+)
>  create mode 100644 
> Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt
> 
> diff --git a/Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt 
> b/Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt
> new file mode 100644
> index 000..f592769
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt
> @@ -0,0 +1,20 @@
> +DT bindings for the Renesas RZ/N1 Reboot Driver
> +
> +== Reboot Driver Node ==
> +
> +The reboot driver is always a subnode of the system controller node, see
> +renesas,rzn1-sysctrl.txt for details.
> +
> +Bindings:
> ++ Required:
> + compatible = "renesas,rzn1-reboot";
> +
> +Example:
> + sysctrl: sysctrl@4000c000 {
> + compatible = "renesas,rzn1-sysctrl", "syscon", "simple-mfd";

Are there other functions for this block? If so, please define a 
complete binding for the block.

> + reg = <0x4000c000 0x1000>;
> +
> + reboot {
> + compatible = "renesas,rzn1-reboot";

Why is this node needed? The driver for "renesas,rzn1-sysctrl" should 
be able to register as a reboot handler/driver/provider.

Rob

Re: [PATCH v3 2/8] DT: reset: renesas,rzn1-reboot: document RZ/N1 reboot driver

[Geert Uytterhoeven]

Hi Michel,

On Thu, Mar 29, 2018 at 9:46 AM, Michel Pollet
 wrote:
> The Renesas RZ/N1 Family (Part #R9A06G0xx) requires a driver
> as part of the sysctrl MFD to handle rebooting the CA7 cores.
> This documents the driver bindings.
>
> Signed-off-by: Michel Pollet 

Thanks for your patch!

> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/renesas,rzn1-reboot.txt
> @@ -0,0 +1,20 @@
> +DT bindings for the Renesas RZ/N1 Reboot Driver
> +
> +== Reboot Driver Node ==
> +
> +The reboot driver is always a subnode of the system controller node, see
> +renesas,rzn1-sysctrl.txt for details.
> +
> +Bindings:
> ++ Required:
> +   compatible = "renesas,rzn1-reboot";

You should list the supported SoC-specific compatible values here.

Quoting what I said on IRC:
1) DT bindings. These should list all compatible values possible/used.
2) DTS: These should list all applicable compatible values,
from most-specific to least-specific (SoC-specific,
family-specific (if exists), generic (if exists))
3 Driver: These should list only the least specific that is
sufficient to get the job done. So usually we have the
family-specific only, except if an SoC needs to be handled
specially, or for historical reasons (DTB backeards
compatibility)

> +
> +Example:
> +   sysctrl: sysctrl@4000c000 {
> +   compatible = "renesas,rzn1-sysctrl", "syscon", "simple-mfd";

Missing SoC-specific compatible value.

> +   reg = <0x4000c000 0x1000>;
> +
> +   reboot {
> +   compatible = "renesas,rzn1-reboot";

Missing SoC-specific compatible value.

> +   };
> +   };

Gr{oetje,eeting}s,

Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds